1. Field of the Invention
The present invention relates to a danger alarm system having a plurality of alarm circuits which are connected via call lines to a central exchange, and more particularly to such a system in which the state of the alarm circuits can be determined in the central exchange by way of testing apparatus and can be displayed by way of evaluation circuits.
2. Description of the Prior Art
Such alarm systems are known, for example, as public fire alarm systems. In general, these systems are modularly designed so that a plurality of lines are usually connectible to the connection component groups in the central exchange. It is therefor required to allocate the correct indications to the alarm circuits which are actually connected and to take care that lines which are not connected do not effect interrupt displays.
This is done in conventional systems, for example, in that a functional interface is simulated at lines which are not connected, for example by means of a specific termination element. However, it is also possible to sort the relaying of the alarm by means of special lines and, in case the same is required, to prevent such relaying by means of interrupting the line. In conventional systems, in such cases, a manual operation must be undertaken in the wiring of the system. This requires a substantial amount of time for screwing and soldering connections; moreover, there is always the danger in such operations that lines are mistaken and incorrectly connected.